1. Technical Field
The present invention relates to an exposure device and a method of exposure.
2. Related Art
For transferring by exposure a fine pattern such as a semiconductor IC pattern to a photosensitive substrate (such as a wafer) on which a resist is applied, it is a common procedure to interpose a projection optical system between a photomask and the wafer, so as to project the image of the mask pattern on the wafer surface.
The ongoing micronization of the design rule has motivated further development of methods for actively controlling a polarization status of the illuminating light or a shape of the opening of the illumination diaphragm. It is known today, for example as disclosed in Japanese Laid-open patent publication No. H05-109601, that resolution with respect to a repeating one-dimensional pattern such as a line-and-space pattern can be effectively upgraded by a combination of (1) a deformed illumination diaphragm that shields a portion of the illuminating light close to the optical axis, thus to transmit only a portion of the illuminating light distant from the optical axis, and (2) a so-called linear polarization of controlling the polarization direction (electric field vector) so as to be parallel to the longitudinal direction of the repeating pattern.
In addition, for improving the resolution with respect to a repeating one-dimensional pattern drawn in two directions, namely transversely and vertically, not only the pattern in one specific direction, for example Japanese Laid-open patent publication No. H07-201723 proposes a combination of (1) a quadruple diaphragm that only transmits the illuminating light in two directions distant from the optical axis, and (2) linear polarization in two directions. The polarization can be caused by various methods, out of which a typical method is placing a polarizing plate immediately anterior to the illumination diaphragm, and disposing a wavelength plate where appropriate, thus to change the polarization direction.